28 replies to this topic

[Jon Rista]

One of my last dark site images, VDB 27 (I believe the blue reflection in the center of the field). This was largely an accidental framing. I was going for Baby Eagle, which ended up just out of the frame. When I took test subs at high ISO, I noticed the blue reflection, and decided to keep the field as it was. I have no idea what the other two interesting reflection nebula are in the field...the information about this region seems hard to come by. (Honestly, I am not absolutely certain which of the three reflection nebula is actually VDB27.)





This was imaged at a dark site, 21.2mag/sq" on the nights this was imaged. Gathered a total of 48 subs, which made for over eight hours of total integration. Equipment used was a Canon 5D III with a Canon EF 600mm f/4 L II lens. Processed 100% in PixInsight.

I had originally gathered less than three hours, however this was one of the images this year that taught me just how much dark current in an unregulated DSLR can really affect IQ. Even after eight hours of total integration, it took a lot more NR work in PI, using TGV, MMT, and ACDNR, to get the noise under control as well as it is, and it still isn't as good as the noise in a 2h20m Orion Nebula image I did on my first visit to this very same dark site. The only difference between the two images...was the temperature. One was at or below freezing, the other was around 20-23C. What a difference 20C has on the amount of dark current noise in the image...it's quite significant.

[Jon Rista]

Corrected the green bias (I can hardly see that on my main workstation screen, but it shows right up on my laptop screen...)

[Jerry Lodriguss]

Hi Jon,

 

Outstanding image.

 

Vdb 27 is actually the nebula just below center on the right side of the frame.

 

The blue reflection nebula in the center of the frame is Ced 30 also known as LBN 169.02-15.54.

 

There's a bunch of Barnard dark nebulae in the area below Ced 30 including B7 B10, B209, B211, B213, B216, B217 and B218.

 

LDN 1495D is the dark complex to the left of center.

 

The image has south to the top. It makes it a little easier to ID stuff if you orient the image with north to the top, but I put south up sometimes for aesthetic reasons also.

 

Check out SIMBAD  based on RA and Dec of the object you want to identify.

 

Jerry

Edited by Jerry Lodriguss, 09 December 2015 - 04:15 AM.

[t_image]

You guys are both awesome! Thanks for sharing on CN!

[Jon Rista]

Thanks, Jerry.

And thanks for all the object IDs! I'll have to check out SIMBAD. I've looked there in the past for some things...I never seem to use it right, especially the Aladin viewer. It scrolls/pans the view really weirdly when I put my cursor over it, and I honestly can never tell what object in the list of results is what.

BTW, south is probably up because that's how things come out of the camera, and I don't think I have any flip image option enabled in PI's demosaicing feature.

[Jon Rista]

You guys are both awesome! Thanks for sharing on CN!

Thanks.

[SunBlack]

Very nice,f4 or stopped? Remember me, 600/4 AIS or Afs?

[srosenfraz]

Gorgeous image, Jon and very well processed.  Since you have PI, you may want to plate solve the image and then use the Annotate Image function to identify what's in the image (as well as others you have).  All the Barnard, NGC, IC, vdB, etc. objects are readily available in PI.  

[Jon Rista]

Very nice,f4 or stopped? Remember me, 600/4 AIS or Afs?

 

I usually stop down to f/4.5, as wide open I tend to get some flare effects. I am thinking about going back to using f/4, though, as stopping down may be hurting resolution (because of that starburst diffraction effect).

 

I am not sure if I remember you. I hardly ever sleep, so my memory is pretty useless these days. So are you using a 600mm f/4 lens for your work as well?

[Jon Rista]

Gorgeous image, Jon and very well processed.  Since you have PI, you may want to plate solve the image and then use the Annotate Image function to identify what's in the image (as well as others you have).  All the Barnard, NGC, IC, vdB, etc. objects are readily available in PI.  

 

Thank you, Scott. I appreciate that.

 

I totally forgot about PI's plate solving. I'll have to run that when I get home. I am curious if it will ID those objects that Jerry identified. Astrometry doesn't even seem to ID them.

[fco_star]

this is an excellent image! like your process ...is perfect!  Congratulations Jon_Rista !

[martl]

Stunning Image and perfect processing, John. Your workflow for denoising must be very good, I hardly see any artifacts. Congrats!

 

CS

Martin

[Jon Rista]

Thanks Francisco, Martin.

 

I do have some pretty specific procedures for NR. I am working on articles on how to use PI, only instead of being workflow tutorials, they will be covering each PI tool in detail. I'll start writing articles for how to use PI's NR most effectively soon here (I hope), and I'll explain how I achieve this kind of result. 

[coinboy1]

Beautiful image! Always look forward to your posts and images as that is what I strive to achieve. So stunning!!

[17.5Dob]

Wow ! I think this might be your best image yet, knowing what it takes to get there

[JoseBorrero]

I'm impressed! Thanks for share!  

[Jon Rista]

Thanks Coin, Dave and Jose. Glad you enjoyed the image.

 

Dave, thanks! For as noisy as the image was at first, it turned out pretty well. I would really love to mosaic this regions, and if I get the chance soon here (clear skies and no moon) I am going to try to hit up the dark site again and get another panel. This year has just been bad for imaging...too much thin cloud cover that just mucks up the works. 

[calypsob]

Nicely done joh, i suppose you could make an aperture mask if you want to avoid spikes. Im not sure how the pix workflow goes but lately i have been removing all of my stars in stratton and processing the background separately from the foreground. When i do the foreground, star layer, i do not stretch it very much and it allows me to control reflections alot better. This is just one workaround that i can think of, though shining a flashlight down the lens with live view on can sometimes help isolate a physical issue as well. This is a great image, you went waaaay deep. And it is very clean. Excellent job!

[Jon Rista]

Thanks Calypsob. Yeah, this one is pretty deep. It is still not as clean from a noise standpoint as I would like...still a lot more color noise than I like, and it's still just a little blotchy. But I think I'd need to double my integration to really fix that, and I don't think that is worth the time. I would rather get 6-8 hours on a neighboring panel, I think. 

 

Anyway, the depth is one of the benefits of 21.3mag/sq" skies and f/4.5 I guess. I actually expected more of the background to end up black...there ended up being a good deal of dust everywhere in the frame. 

 

I've seen a couple images of this region done with a KAI-11002...and WOW. Freakin phenomenal. Not as much resolution, actually, but man this region of space has some incredible dark structure. I think it's becoming one of my favorite regions. I'd love to get a large mosaic of the whole region from Perseus to Pleiades to Hyades. If only I had enough clear skies to do it.

[andysea]

Beautiful result! 

[mark in ventura]

What a wonderful image! I wonder if I should try this with a cooled camera. Your camera is modded but not chilled and you have a great result. Did you dither? Thanks for the inspiration although it remains to be seen if i can get there with an SQM of 20.4. 

[Jon Rista]

Thanks Andy, Mark.

 

My camera is actually unmodded. It is both unmodded and unchilled. Sensor temps (from EXIF) were recorded at 19-23C. Warm enough to be somewhat problematic from a dark current standpoint. 

 

I do dither. I have actually optimized my dithering routine. I dither as infrequently as I can get away with, and I dither as quickly as possible. I have been using BYE thus far, at it's default settings with aggression at 4-5, it takes forever to settle. I started dithering by relative timespans, rather than every frame. With shorter subs (up to 3-4 minutes), I'll dither every few frames. With longer subs (5-9 minutes), I'll dither every couple frames, and longer subs (10 minutes and longer) I dither every frame. I relaxed the settling factors, though, because my seeing and tracking usually don't allow me to "settle" anywhere remotely close to 0.25, and trying to just means dithering takes the fully allotted and allowed time (which I believe is around two minutes), then it just gives up. I also nuked the cooldown, setting it to the minimum time of 1 second. With a settle factor somewhere between 0.45-0.75, depending on my seeing, and a cooldown of 1s, I can dither within 5-15 seconds, and be back to imaging...rather than having to wait about 2 minutes between every frame.

 

When you use shorter subs and get LOTS of them, you don't need to dither every frame. Sigma rejection is more than capable of identifying the same hot pixel in a small number of frames out of the whole lot as outliers, and will happily reject them. When you get up into 10 minute and longer subs, then you should dither every frame...you'll likely have a lot fewer, so dithering every frame really counts. 

[srosenfraz]

 

Gorgeous image, Jon and very well processed.  Since you have PI, you may want to plate solve the image and then use the Annotate Image function to identify what's in the image (as well as others you have).  All the Barnard, NGC, IC, vdB, etc. objects are readily available in PI.  

 

Thank you, Scott. I appreciate that.

 

I totally forgot about PI's plate solving. I'll have to run that when I get home. I am curious if it will ID those objects that Jerry identified. Astrometry doesn't even seem to ID them.

 

 

Hi Jon -

 

IIRC, when I annotated my image of this area, the only thing PI didn't identify were the LDN (and LBN) objects.  There isn't a catalog with these objects built into the default config for PI.  There is a way to incorporate other catalogs, but I haven't stumbled across an LDN or LBN catalog that's formatted for use with PI.  It does have catalogs built in for NGC, IC, PGC, vdB, Barnard, Sharpless, Arp, plus several other star catalogs.

[Jon Rista]

I solved and annotated the image. I threw a bunch of catalogs at it, including Barnard and VDB. The Barnard one annotated a few things, but for some reason it still isn't identifying VDB27. I set up the VDB catalog to render in green, and I'm not seeing any of that anywhere in the field.

 

Anyway, here is the annotated version:

 

 

 

[17.5Dob]

 

Anyway, the depth is one of the benefits of 21.3mag/sq" skies and f/4.5 I guess. I actually expected more of the background to end up black...there ended up being a good deal of dust everywhere in the frame. 

 

 

You're really making me ready to get all of the power supplies/ adapters set to go, since the "slowest" I can go is f4, then on down to f2.8.